﻿// Copyright 2004-2011 Castle Project - http://www.castleproject.org/
// 
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// 
//     http://www.apache.org/licenses/LICENSE-2.0
// 
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#region 导入名称空间

using System.Reflection;
using LightWork.DynamicProxy.Contributors;
using LightWork.DynamicProxy.Generators.Emitters;

#endregion

namespace LightWork.DynamicProxy.Generators
{
    public abstract class MethodGenerator : IGenerator<MethodEmitter>
    {
        private readonly MetaMethod method;
        private readonly OverrideMethodDelegate overrideMethod;

        protected MethodGenerator(MetaMethod method, OverrideMethodDelegate overrideMethod)
        {
            this.method = method;
            this.overrideMethod = overrideMethod;
        }

        protected MethodInfo MethodOnTarget => method.MethodOnTarget;

        protected MethodInfo MethodToOverride => method.Method;

        public MethodEmitter Generate(ClassEmitter @class, ProxyGenerationOptions options, INamingScope namingScope)
        {
            var methodEmitter = overrideMethod(method.Name, method.Attributes, MethodToOverride);
            var proxiedMethod = BuildProxiedMethodBody(methodEmitter, @class, options, namingScope);

            if (MethodToOverride.DeclaringType.IsInterface)
                @class.TypeBuilder.DefineMethodOverride(proxiedMethod.MethodBuilder, MethodToOverride);

            return proxiedMethod;
        }

        protected abstract MethodEmitter BuildProxiedMethodBody(MethodEmitter emitter, ClassEmitter @class,
            ProxyGenerationOptions options, INamingScope namingScope);
    }
}